Self-cleaning filter arrangement with activation signal for floor care apparatus

ABSTRACT

A floor care apparatus has a filter with an intake and out take. A first pressure sensor is arranged on the intake while a second pressure sensor is arranged on the out take. A controller connects to the sensors to receive signals indicative of relative pressure. Whenever a predetermined pressure differential between the signals is achieved, an undesirable load on the filter is deemed occurred and initiation of a self-cleaning of the filter begins. In this manner, filter cleaning only occurs on an as-needed basis and user intervention is avoided, thereby adding convenience. The controller is also able to ascertain a clogged airway condition. Various features contemplate pressure sensor signals arranged to scale suction as positive pressures, meeting the predetermined pressure differential at other than a maximum pressure differential between the first and second pressure sensors, and scaling the predetermined pressure differential relative to the maximum pressure differential.

TECHNICAL FIELD

The present invention relates generally to the floor care field. Moreparticularly, it relates to a floor care apparatus, such as a canisteror upright vacuum cleaner, having a self-cleaning filter and arrangementtherefor. Particular aspects relate to activation of signals initiatingself-cleaning, without user intervention, and doing so only on anas-needed basis.

BACKGROUND OF THE INVENTION

Whether canister or upright, vacuum cleaners in all of their designs andpermutations have become increasingly popular over the years. Ingeneral, vacuum cleaners incorporate a suction fan motor, attendant dirtcup or dust bag and a nozzle assembly fluidly and mechanically connectedto one another that suck up dirt and dust during operator movementacross a dirt-laden floor. Specifically, an agitator within the nozzleassembly rotates to beat the nap of a carpet and dislodge dirt and dustduring a time when an operator manipulates the cleaner back and forth.Dirt and dust then enter the cleaner and flow in an airstream toward themotor. Upstream of the motor, the dust and air are separated andparticles are trapped in the dirt cup or dust bag. Upon filling, thedirt cup or dust bag can be emptied or discarded and the processrepeated.

While dirt cups allow users to visually inspect whether the cup is fulland requires dumping, filters associated with the cups become saturatedwith fine particles during filling. Over time, such fine particlesrestrict airflow and reducing cleaning efficiency of the vacuum cleaner.Eventually the cleaning efficiency of the vacuum cleaner becomes soimpaired it is necessary for the operator to either clean or replace thefilter in order to achieve the desired level of cleaning. However,filter cleaning and replacement requires manual user intervention, andboth can be messy. Filter cleaning performed unnecessarily also acts toprematurely fail the filter material.

Accordingly, the floor care arts have need of simple, yet effective,arrangements for truly self-cleaning filters that minimize or eliminateuser involvement. They should also only operate when necessary to extendfilter service life and increase cleaning efficiency. Naturally, anyimprovements should further contemplate good engineering practices, suchas relative inexpensiveness, stability, ease of implementation, lowcomplexity, etc.

SUMMARY OF THE INVENTION

In accordance with the purposes of the present invention as describedherein, an improved floor care apparatus is provided. The apparatus maytake the form of a canister or an upright vacuum cleaner or may embodyan extraction cleaning device or other hereinafter developed product. Inthis regard, the present invention relates to a vacuum cleaner,extractor or the like equipped with a more efficient and effectivefilter cleaning mechanism. Advantageously, the present invention allowsfor the quick and easy automatic cleaning of dirt and debris from afilter including particularly fine particles from the pores of thefilter. As a result each filter has a longer service life and theapparatus may be operated at a higher cleaning efficiency over theentire length of that extended service life.

In one embodiment, a floor care apparatus has a filter with an intakeand out take. A first pressure sensor is arranged on the intake while asecond pressure sensor is arranged on the out take. A controllerconnects to the sensors to receive signals indicative of relativepressure. Whenever a predetermined pressure differential between thesignals is achieved, an undesirable load on the filter is deemed havingoccurred and initiation of a self-cleaning of the filter begins. In thismanner, filter cleaning only occurs on an as-needed basis and userintervention is avoided, thereby adding convenience. The controller isalso able to ascertain a clogged airway condition. Various featurescontemplate pressure sensor signals arranged to scale suction aspositive pressures, meeting the predetermined pressure differential atother than a maximum pressure differential between the first and secondpressure sensors, and scaling the predetermined pressure differentialrelative to the maximum pressure differential.

In other embodiments, the controller operates with a visual indicator toindicate a self-cleaning operation or clogged airway condition. Pressuresensors also typify diaphragms, transducers, or the like. Filters are ofthe type found in dirt cups of bagless vacuum cleaners or other.

In the following description there is shown and described possibleembodiments of the invention, simply by way of illustration of one ofthe modes best suited to carry out the invention. As it will berealized, the invention is capable of other different embodiments, andits several details are capable of modification in various, obviousaspects all without departing from the invention. Accordingly, thedrawings and descriptions will be regarded as illustrative in nature andnot as restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings incorporated in and forming a part of thespecification, illustrate several aspects of the present invention, andtogether with the description serves to explain the principles of theinvention. In the drawings:

FIG. 1 is a perspective view of a floor care apparatus, in this instancean upright vacuum cleaner with dust bag, constructed in accordance withthe teachings of the present invention;

FIG. 2 is a perspective view of a floor care apparatus, in this instancea canister vacuum cleaner, constructed in accordance with the teachingsof the present invention;

FIG. 3 is a perspective view of a floor care apparatus, in this instancean upright vacuum cleaner with dirt cup, constructed in accordance withthe teachings of the present invention;

FIG. 4 is a cross-sectional view of the dirt cup of FIG. 3;

FIG. 5 is a diagrammatic view of an arrangement of sensors on a bagmount;

FIG. 6 is a detailed top perspective view of a filter assembly;

FIG. 7 is a graph of suction variation regarding the sensors of FIGS. 4and 5; and

FIG. 8 is a diagrammatic and circuit view of a representative embodimentof a controller and visual indicator for a self-cleaning filterarrangement.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

In the following detailed description of the illustrated embodiments,reference is made to the accompanying drawings that form a part hereof,and in which is shown by way of illustration, specific embodiments inwhich the invention may be practiced. These embodiments are described insufficient detail to enable those skilled in the art to practice theinvention and like numerals represent like details in the variousfigures. Also, it is to be understood that other embodiments may beutilized and that process, mechanical, electrical, arrangement, softwareand/or other changes may be made without departing from the scope of thepresent invention. In accordance with the present invention, methods andapparatus for self-cleaning floor care apparatus and attendant control,including activation signal are hereinafter described.

Reference is now made to FIG. 1 showing a floor care apparatus of thepresent invention. The apparatus illustrated exemplifies an uprightvacuum cleaner 10 comprised generally of a housing 14 that comprises thenozzle assembly 16 and the canister assembly 18. The canister assembly18 further includes the handle 20 and the hand grip 22 for maneuveringthe cleaner during use. The hand grip 22 carries a control switch 24 forturning the vacuum cleaner 10 on and off while electrical power issupplied from a standard electrical wall outlet through a cord and plugassembly 17. The handle 20, among other things, carries a visualindicator 23 of sorts to indicate a self-clean, replace filter orclogged airway condition as will be described below. At the lowerportion of the canister assembly 18, rear wheels (not shown) areprovided to support the weight of the vacuum cleaner 10. A second set ofwheels (not shown) allow the operator to raise and lower the nozzleassembly 16 through selective manipulation of a height adjustment switch28. To allow for convenient storage of the vacuum cleaner 10, a footlatch 30 functions to lock the canister assembly 18 in an uprightposition, as shown in FIG. 1. When the foot latch 30 is released, thecanister assembly 18 may be pivoted relative to the nozzle assembly 16as the vacuum cleaner 10 is manipulated to clean the floor.

Also, the canister assembly 18 carries an internal chamber 32 thathouses a suction generator or fan motor 33 (i.e. a state of the art fanand motor combination) and a dust bag 34 for removing dirt or dustentrained in the air stream as it passes in an airflow path from thenozzle assembly 16 to the suction fan motor. During use, the suction fanmotor 33 creates the suction airflow in a well known manner.

In the nozzle assembly 16, a nozzle and agitator cavity 36 houses anagitator 38. The rotary scrubbing action of the agitator 38 and thenegative air pressure created by the suction fan motor 33 cooperate tobrush and beat dirt and dust from the nap of the carpet being cleanedand then draw the dirt and dust laden air from the agitator cavity 36 tothe dust bag 34. Specifically, the dirt and dust laden air passesserially through a suction inlet and hose (not shown) and/or anintegrally molded conduit in the nozzle assembly 16 and/or canisterassembly 18 as is known in the art. Next, it is delivered into thechamber 32 and passes through the porous walls of the dust bag 34. Thebag 34 serves to trap the suspended dirt, dust and other particlesinside while allowing the now clean air to pass freely through the wallthereof. Clean air then flows through the suction fan motor 33, finalfiltration cartridge, including filter 42, and to the environmentthrough the exhaust port 44.

With reference to FIG. 2, a floor care apparatus of the presentinvention in this embodiment exemplifies a canister vacuum cleaner 210comprised generally of a base assembly 212 and a nozzle assembly 214.Although not shown, the base assembly contains a suction fan motor thatcooperates with an agitator 216 in the nozzle assembly for sucking updirt and dust in the manner previously described for the uprightcleaner. A wand 218 mechanically and fluidly connects to the nozzleassembly and facilitates the sucking up of dirt and dust. In variousembodiments, it comprises a unitary, telescopic or connecting section ofpipe. Near the base assembly, a hose 220, flexible for usermanipulation, connects thereto and likewise facilitates cleaning.Finally, a handle 230 having ends 217, 219 connects mechanically andfluidly to both the wand 218 and the hose 220 and enables an airflowpath between the nozzle assembly and the suction fan motor of the baseassembly.

In either floor care apparatus embodiment, the cleaners have a dust bagand filter within a housing configured to enable the indication to usersof a replace filter, cleaning of filter required, or clogged airwaycondition during use.

With reference to FIG. 3, a floor care apparatus of the presentinvention in this embodiment exemplifies another upright vacuum cleaner10 including a housing 14 with both a nozzle assembly 16 and a canisterassembly 18, as before. In addition, the canister assembly 18 includes acavity or receiver 64 for receiving and holding a dirt cup or collectionvessel 50. The dirt cup is removable in the cavity and when full, uponvisual inspection, users pull the dirt cup from the cavity and empty itscontents.

The operation of the airflow through the dirt cup 50 will now bedescribed in greater detail with reference to FIG. 4. During normalvacuum cleaner operation, the suction generator draws air from thesuction inlet through the dirt cup 50 where dirt and debris is trappedand then exhausts clean air from the exhaust port. As the vacuum cleanercontinues to operate, fine dirt particles not removed from the airstreamby the cyclonic action in the annular space S is stripped from theairstream and trapped by filter media 62 of a filter 52. The filter 52may include a sidewall 54, a hub 56 and multiple partitions 58 extendingbetween the hub and the sidewall (see FIG. 6). The partitions serve todivide the filter 52 into multiple sections 60. Over time, these finedirt particles begin to close off the pores in the filter media 62thereby restricting airflow. This not only causes the motor of thesuction generator to run hotter and at a lower efficiency, it alsoreduces airflow thereby adversely affecting the cleaning efficiency ofthe vacuum cleaner. Consequently, the airflow may become so restrictedas to prevent the vacuum cleaner from cleaning properly. It is thennecessary to either clean or replace the filter 52.

The present invention, in one aspect, allows the filter 52 to beself-cleaned in situ in a very convenient and efficient manner.Specifically, with reference to FIG. 4, a stepper motor may be activatedto rotate an air guide 86 through various arcs by means of attendantmeshing drive gears 80, 82. This functions then to rotate the air guide86 so that the outlet 90 thereof is exactly aligned over or inregistration with one of the sections 60 of the filter 52. In thismanner, the suction generator draws clean air through the inlet 88 ofthe air guide 86 and then directed by the outlet 90 thereof through thesingle individual section 60 of the filter 52 with which the outlet isaligned. Since the clean air is moving through the selected section 60of the filter 52 in a direction opposite that of normal operation, dirt(and particularly fine dirt from the pores of the filter), is forcedfrom or blown out of the filter media 62. For a further description ofthis technology, reference is taken to U.S. patent application Ser. No.11/633,902, incorporated herein, in its entirety, by reference.Alternatively, however, other self-cleaning filters contemplate variousmechanical shaking, flicking, beating, etc., of filter material to shakeloose entrenched dirt and debris. In either, the cleaning cycle maylast, for example, from about 1 to about 30 seconds and more typicallyfrom about 3 to about 15 seconds. Section-by-section cleaning of thefilter can also be filter wide cleaning and still be embraced within theinvention.

With reference to FIG. 4, the dirt cup 50 includes sensors P_(A), P_(B)to determine undesirable loads on the filter, thereby indicating a dirtyfilter requiring cleaning, especially self-cleaning, or a clogged airwaysomewhere else in the cleaner. FIG. 4 shows the sensors P_(A), P_(B)arranged about the filter 62. In this configuration, the sensor P_(A) ispositioned in a pre-filter location, directly upstream of the filter,while the sensor P_(B) is positioned in a post-filter location, directlydownstream of the filter. The sensors P_(A), P_(B) may be attached tothe dirt cup 50 (e.g., to walls of the dirt cup), to the filter 52, orotherwise positioned in the dirt cup 50. The sensors may take the formof diaphragms, pressure transducers, or the like, having electricaloutput signals indicative of a measured or observed pressure. They mayalso embody a type to sense strain/force of air pressure (differential,absolute and/or combinations). The sensors P_(A), P_(B) may also be usedin a vacuum cleaner including a dust bag, such as the cleaners of FIGS.1 and 2. FIG. 5 shows the sensors P_(A), P_(B) positioned on a bag mount506. As shown, sensor P_(A) is positioned upstream of a dust bag (notshown), while sensor P_(B) is positioned downstream of the bag. Thesesensors may take the form of pressure ports having small, flexiblevacuum tubes that connect the ports to a transducer. Of course, thesensors P_(A), P_(B) may take any form and location, other sensors andother locations are also contemplated.

In FIG. 8, each of the pressure sensors P_(A), P_(B) are connected to aprocessor 81. Examples of preferred processors include, but are notlimited to, microprocessor(s), application specific integratedcircuit(s) (ASIC), software or other programming, or the like.Regardless of type, the processor is configured to sort a relativedifference between each of the signals of the sensors and appropriatelyprovide signals to initiate self-cleaning 83 and to power a visualindicator or display 23 to show the filter self-cleaning or a cloggedairway condition. In this regard, the processor is configured withvarieties of external power supplies (Vcc), clock signals (Clock),resistors R, transistors (not shown), etc. to drive a visual indicator23. In one instance, the visual indicator is a segmented display havingtwo segments, one each for self-clean and clog that light to showvarious status of the cleaner.

Also, the sorting of relative differences between signals of thepressure sensors may be further enhanced via comparison to a referencepressure P_(R) stored, for example, as a single or table of values in anattendant memory M. In this regard, reference pressures include, but arenot limited to, an ambient pressure external to the floor careapparatus, a minimum pressure that must be overcome before providing anyvisual indications to users, or boundary conditions that must besatisfied. The memory also contemplates resetting functionality thatoccurs when users empty dirt cups, replace full dust bags with new,empty ones, or clean or replace filters.

In other embodiments, FIG. 7 shows the relationship between the sensorsand how this is used to initiate a self-cleaning of the filter, such asby the signal labeled self-clean emanating from the controller 81 inFIG. 8. Namely, the controller is programmed to recognize a prescribedmagnitude ΔP' as the signal representing a “filter undesirably loaded”or a “filter needs cleaning” condition. Upon recognizing this condition,the controller initiates the self-cleaning function, previouslydescribed. The ΔP', however, need not be a true maximum ΔP_(max) betweenP_(Amax) and P_(Bmin), as shown. That is, ΔP' can be a value of abouthalf to three-fourths, or so, or any percentage of the ΔP_(max) provenoptimal to maintain an adequate average airflow (e.g., suction). Inother words, waiting until the filter is fully dirty or the dust bag iscompletely fill/saturated may lead to prolonged reduction in suctionand/or suction motor damage.

It should also be understood that due to pressure sensor P_(A), FIGS. 4and 5, being installed immediately prior to (upstream from) the filteror bag, a clog occurring anywhere in an airway (especially in airwayhoses or housing conduits) therefore upstream from both sensors P_(A)and P_(B), causes a spike in the pressure at P_(A) and P_(B), minimizingthe pressure differential, given as ΔP_(min). In this way, twocontrasting signals, ΔP' and ΔP_(min), distinguish between self-cleaningof the filter and a clogged airway condition, respectively. Uponrecognition of the latter, the controller would activate the visualdisplay 23 indicating a clog and that such must or should be cleared.However, boundary conditions must be further established todifferentiate ΔP_(min) and ΔP_(omin) where pressure differential at thebeginning of filter loading may actually be less. One way to accomplishthis is to define a pressure level P_(C) which both P_(A) and P_(B) mustsimultaneously exceed during a clogged airway condition or sealedsuction. P_(R) in FIG. 7 can also set this P_(C) value. A lower limit onelectrical current would also distinguish between ΔP_(min) and ΔP_(omin)as motor amp draw at the clog condition would be a minimum. In thegraph, it will be noticed that it is preferred to scale suction of thefloor care apparatus as positive pressures and do so in a relativerange, such as between 0 to about 3 psi. Grams woodflour represents theother axis and preferably ranges from 0 to about 1800. Of course, otherscales and arrangements are possible.

The foregoing was chosen and described to provide the best illustrationof the principles of the invention and its practical application tothereby enable one of ordinary skill in the art to utilize the inventionin various embodiments and with various modifications as are suited tothe particular use contemplated. All such modifications and variationsare within the scope of the invention as determined by the appendedclaims when interpreted in accordance with the breadth to which they arefairly, legally and equitably entitled. Relatively apparentmodifications, of course, include combining the various features of oneor more figures with the features of one or more of other figures.

1. A floor care apparatus, comprising: a filter with an intake and out take; and a first pressure sensor arranged on the intake and a second pressure sensor arranged on the out take, wherein a predetermined pressure differential between the first and second pressure sensors indicates an undesirable load on the filter and causes activation of a signal to initiate a self-cleaning of the filter.
 2. The floor care apparatus of claim 1, wherein a controller responds to the predetermined pressure differential between the first and second sensors and causes the activation of the signal.
 3. The floor care apparatus of claim 2, wherein the controller distinguishes between the signal to initiate the self-cleaning of the filter and a clogged airway.
 4. The floor care apparatus of claim 1, further including a visual display identifying the self-cleaning of the filter.
 5. The floor care apparatus of claim 3, further including a visual display identifying the clogged airway.
 6. The floor care apparatus of claim 3, wherein the controller distinguishes between the signal to initiate the self-cleaning of the filter and the clogged airway by comparison to a predetermined threshold.
 7. The floor care apparatus of claim 1, wherein the filter is disposed in a dirt cup.
 8. The floor care apparatus of claim 1, wherein the first and second pressure sensors are both arranged to scale suction of the floor care apparatus as positive pressures.
 9. The floor care apparatus of claim 1, wherein the predetermined pressure differential is a pressure differential other than a maximum pressure differential between the first and second pressure sensors.
 10. The floor care apparatus of claim 9, wherein the pressure differential other than the maximum pressure differential is in a range from about one-half to about three-quarters percent of the maximum pressure differential.
 11. The floor care apparatus of claim 1, wherein the filter is not a dust bag.
 12. A floor care apparatus, comprising: a filter with an intake and out take; a first pressure sensor arranged on the intake and a second pressure sensor arranged on the out take, both the sensors providing a signal indicative of pressure; and a controller in receipt of the signals from the sensors, wherein a predetermined pressure differential between the signals indicates an undesirable load on the filter and causes activation of another signal to initiate a self-cleaning of the filter, the controller able to distinguish between the signals from the sensors to either initiate the self-cleaning of the filter or to indicate a clogged airway condition.
 13. The floor care apparatus of claim 12, wherein the first and second pressure sensors are both arranged to scale suction of the floor care apparatus as positive pressures in a range between 0 and about 3 psi.
 14. The floor care apparatus of claim 12, wherein the predetermined pressure differential is a pressure differential other than a maximum pressure differential between the first and second pressure sensors.
 15. The floor care apparatus of claim 14, wherein the pressure differential other than the maximum pressure differential is in a range from about one-half to about three-quarters percent of the maximum pressure differential.
 16. The floor care apparatus of claim 12, further comprising a visual indicator to indicate a self clean, replace filter, or clogged airway condition.
 17. A method of using a floor care apparatus, comprising: providing a filter with an intake and an out take; arranging a first pressure sensor on the intake and a second pressure sensor on the out take; determining a pressure differential between the first and second pressure sensors; and initiating a self-cleaning of the filter based on the determining.
 18. The method of claim 17, wherein the initiating the self-cleaning occurs when the pressure differential reaches a predetermined value.
 19. The method of claim 18, further including connecting a controller to the first and second pressure sensors for ascertaining whether the pressure differential reaches the predetermined value.
 20. The method of claim 17, wherein the determining further includes calculating a maximum pressure differential.
 21. The method of claim 17, further including ascertaining a clogged airway condition.
 22. The method of claim 17, further including providing a visual indicator to indicate a self clean, replace filter, or clogged airway condition. 